Improved gold washer and amalgamator



T. V, TAVNAY.

Gold Washer.

Patented July 7, 1857.

. IRVEV/LTW v fl w NITED "STATES PATENT OFFICE.

'r. v. 'TAVNAY, OF SAN FRANCISCO, CALIFORNIA.

. -l-'M-PROVED co o -WA-SH ER AN D AMALGAM ATO R.

To-allwhom it may concern: Be it known that. I, T. V. TAVNAY,-of the cityandcounty of San :Franciscofinthe State of California,.haveinvented a new and useful improvement onthe-sluice, the rifflebox, and amalgamatorvfor thepurpose of washing and amalgamatinggoldand silver,: by which joint processZI save the finest particles of these metals foundEfrom experience and despite all improvements known to be carried away and lost ;-a'nd:-.I do hereby declare that the following is a full,-,clear, and exact description of theconstruetion and operation of the same, reference being had-to the annexed drawings, making apart; of this-specification, inrwhich Figure 1 is a perspective view; Fig.-,2,a longitudinal elevation, and Fig. 3 a transverse section.-

Xis .the. endof anordinary sluice,- whichis furnish'ed with screens to keep out the; gravel, and may have metallic plates coated withmer- 'cury -towardathe end, or otherwise modified according-to circumstances. 'Every riffle, in themachineis filledwith mercury and every plate is coated :with the same.

:'K is :azscrcen to receivethe -water,-sand,fand finetgiold only, the coarse gold having beenrevtained in the sluice; H, platform to throw off the-coarse sand which canuotpass through-K,

.whose wirewas cut from a piece of the same used inzthe machine worked by me; A ,-cascadei-box containing metallic plates to form a series of fallsorcascades. The board G is cleaning.

I B isthe firstriffle-boXwith riffles at a" a: :r ww;ov,and-metallic platesat No. 5, and plates also attached toeach movable vane 1 2 3, made:

thus for cleaning; 0, second riffle-box containing the movable vane No. 4,F, with -metallic plate 6, and placed between the two boxes, i

before or behind the 'pointfixed t-hereto,.in:

such away as-vto receive the fall of the cascade; toward" the center of the lower plate and react or changet-he current of water; Nos. -7 and 8;

are also coated plates. The three knobs atv 0; :0 o Fig. 1, outside thebox are for the purpose? 1 of communicating el'ectricity,if' found neces-? sary. D is a box atthe end of the machine to? retain any overflowing mercury. Metallic g-platescan be placed-in this box in the same way. as in cascade-box'A if found necessary. 0 is a slide, which rises or falls so as to regulate the ;passage of the-water, which must have force enough barely suflicient to carry off the sandand nomore. w,

:Torender my description as succinct and clearv as possible,l must enterinto a few preliminary remarks, whichI believe necessary, as no drawing can in this case convey a perfoot idea of the improvements effected.

The fine gold containedin some alluvial soils and in the rivers, in the form of thin flakes or scales, is often found to be so light and minute that it escapeslfrom the miner despite all the meansemployed up to this time. The same loss'takes place in the quartz-mills, none of theprocesses in use-being. found adequate to the purpose ofpreserving the fine escaping particles above referred to. The diifficulty existing is not always found to be the same in both cases of quartz and placer mining, although the great'tenuityof the flakes or scales will be found to occur inboth.

-In the rivers or soilsthe particles of gold :metal are generally pure-i. 0., incorporate with other-bodies. In pulverized quartz a simple inspection will prove that whatever may be its finenesspar'ticles of gold may be found adheringto one of quartz orpyrites. In proportion asthequartz or pyrites is large the particle of gold adhering is less likely to be saved. Amalgamation takes place according to the specific .gravityof the gold, as well as according to its affinity or attraction to mercurry.

Insupposing that according to its specific gravity eachparticle of. pure gold must. amalgamate,.those particles adhering to quartz or to pyrites have the more or less chance of being saved according to thesize of the foreign body,- which is lighter than gold or even than mercury itself. One particle composed of onehalf quartz, the other half of gold, will have :fifty per cent. les's'chance of being saved by the mercury. Another particle composed of onepart gold-andthree parts of foreign matter will have seventy-five per cent. less chance, the current of water on the surface of the mercury being equal in botlrcases.

It sometimes happens that a particle of gold, although in contact with mercury on one of its sides, will escape the attraction, pass through, and become lost in the tailings. This takes place most often in those placers where, having deposited in a soil through which calcareous salts have more or less filtered, the particles of gold have been covered over by a coating impervious to mercury; anditis often I the case that many particles of gold, spread in scales almost as light as gold-foil, float on top of the water. I have, I believe, got over all these difficulties by means of aprocess as simple as it is easy of application wherever mining can be carried on.

Having at different times mixed gold and mercury in vases of different metals-such as copper, lron, tin, silver--I remarked that when any part of the vase was attacked by the mercury and adhered to it, fine scales of gold were easily caught on those parts, sticking thereto forcibly. I was thereby encouraged to make a few experiments on the subject, and discovered the most important of the principles on which I have based my process of washing and amalgamating. I remarked, also, in examining some slnices and riffle-boxes, that the floating particles of gold jumped over the riffles, never came in contact with the mercury, and were carried away even quicker than the sand. To obviate this difficulty I combined currents together in such a Way as to form little whirlpools, into which the floating particles would be attracted, and after turning therein for some time would be submerged.

The following is therefore an expose of my process based on the forgoing remarks.

Give the particles of gold every possible chance of being retained in Whirlpools, or by placing in their way a great surface of mercury, havingpreviously disengaged them when necessary from any coating of foreign matter. By having sheets of iron in the bottom of the sluice, the mere friction therewith of the particles of gold will free the latter in part, if not wholly, from a portion of the foreign matter which may be adhering thereto. Then carried by the current against a metallic plate, covered over with mercury and so placed as to cause a fall or cascade, the gold being heavier than the water will go with a certain force against the plate, to which it will be found attached, or otherwise will have retained enough mercury to keep it in the riffle. The bottom of my riffle-box is furnished with movable vanes, which regulate the current of.

water, keeping it an equal height and making it as even and as steady as possible. The vanes, which are placed in front of the riflles, have attached to their lower edges plates coated with mercury, against which most of. 1 the floating particles of gold will be found ad-;. hering. Those that may escapehere remain, in the whirlpool formed close to the vane, orv in that which will be found under the loweri edge of the deep riffle placed behind the vane. The height of the fall in this riffle is calculated in such a way that the water will have exactly the power (and no more) to carry off the sand, only leaving in the riffle every particle of metal or any other body heavier than sand.

It may perhaps be necessary sometimes, on account of the great tenuity of the metallic scales, to have recourse to electricity. In that case galvanic batteries of any kind are to be placed so as to act on the mercury contained in the riffles, through the means of metallic knobs which go through the sides of the boxes. This constant current of electricity gives to the mercury the property of having a greater affinity for gold. I have,however, 7 after long and repeated experiments, tried under many different states and conditions, never been able to find any particle of gold in the sixth riffle, and therefore never had oc casion for recourse to electricity.

One of the most important conditions for the washing of gold is to receive in the riffle-1 boxes set apart for the amalgamation of fine gold none but the finest sand possible. For this purpose, all the larger particles of gold having been caught in a separate part of the sluice, I interpose screens, which receive the gravel, sand, and fine gold, allowing only the two latter to pass through into my riffle-box, where they meet the plates, Whirlpools, and cascades referred to. Where I have to operate on ground quartz the plates coated with mercury are found to be of the greatest use. They will even retain a particle of pyrites to which is sometimes found attached a single molecule of gold. As the plates would be found in a very short time covered over with metallic particles, and would no longer offer the same facilities for the amalgamation of the golden particles, I from time to time throw into the sluice a few drops of mercury, which spread themselves through the body of sand carried along by the current, and arrive on the plates in the form of little globules, which, attachingthemselves to the surface of the particles of gold already adhering thereto, form an amalgamated mass, which is soon driven by the constant action of the sand and current to the lower edge of the plates, and detaching itself therefrom by degrees in lumps or large drops remains in the riffle. I

The box at the extremity of the machine is to retain the globules of mercury which may escape by accident or from the overflowing of the riflles.

The machine will require more or less inclination according to the quality of the soil, its density, or the quantity of titanate of iron or other heavy bodies which it may contain.

Consider the machine (or riffle-boxes) to be properly inclined and ready for work, at the moment when elevating it gradually I find the water to have a current just sufficient to carry 0E easily, smoothly, and regularly the whole mass of sand washed.

The breadth of the riffle-boxes must be cal culated according to the quantity of water to be employed. I have never required much more than one-eighth of an inch of water, so

that one inch of water would require the rifflebox to be about seven inches broad. When the particles of gold become finer and are the more likely to float, then the water must be decreased in depth and spread more evenly, if possible.

My process of washing requires but little capital and no difficult or costly work to be done. Once the machine is in its place one man can watch it and attend to it while fifteen or even twenty men are employed throwing dirt into the slnices. In the quartz-mill the only labor required is to clean the screens once about every half-hour. It can, of course, be

used to amalgamate silver as well.

Having thus fully explained the nature of my invention and shown how the same may be reduced to practice, what I claim therein as new, and desire to secure by Letters Pat cut, is-

In gold washers and amalgamators, the metal plates coated with mercury, the riffles, vanes, and reacting-surfaces, arranged and located substantially as herein described, and for the purpose set forth.

Mariposa, 12th October, 1855.

T. V. TAVNAY.

Witnesses:

O. GRANDVOINET, G. E. GARDNER. 

